A Weak GNSS Signal Acquisition Algorithm: Based on Stochastic Resonance

Acquisition of weak global navigation satellite system (GNSS) signals has been a difficult problem in high sensitivity satellite navigation receivers. Aiming at the problem,a GNSS signal acquisition algorithm based on stochastic resonance(SR) is proposed. A previous study has shown that SR technique provides a new perspective to detect weak signals and it can be applied to GNSS signals.Firstly, the method uses frequency compensation and coherent filtering to increase signal power. Secondly, the delay and multiplication algorithm is used to acquire pseudo-random(PRN) code. Therefore, GNSS signal can be processed to get periodic signal. Finally, the Doppler frequency shift can be obtained by twice sampling and adaptive processing. In this process, the problem of poor stability and adaptability of SR acquisition is solved. The effectiveness of our proposed method was verified by the simulations. The simulation results indicate that the new algorithm based on SR can effectively complete GNSS signal acquisition in low signal to noise rate(SNR) conditions.